VLAN (Virtual Local Area Network) is a logical LAN that have separate broadcast domain. VLAN is often called LAN virtualization. VLAN groups ports of the switch and each group are given different VLAN-ID and VLAN name. Before getting deep into VLANs, we need to have understanding of broadcast domains and collision domains. Understanding VLANs in switching world is a very basic step that will get you into networking world.
Understanding VLANs in Switching World
Broadcast Domains and Collision Domains
In the figure shown below, we take a look at simple broadcast network. If one device sends a broadcast frame out on one interface then switch forwards the copy of the frame out all the interfaces except the one that it came from. All the devices are fed that broadcast message regardless of whether a device needs to receive that data or not. This implies whichever PCs received the broadcast message; they all are in one broadcast domain.
Understanding VLANs in Switching World…show more content… The increase in the number of PC and switches will obviously result in more broadcast messages being flooded out into the network. And thus one thing leads to another; these broadcast messages consume the major portion of the network bandwidth in the same ratio in which the devices were populated. Hence we should make an effort to limit the size of the broadcast domain so that we can manage our network in an efficient manner. There is a way to segment the broadcast domain by introducing router. What router does is, it breaks the broadcast domain as every interface in the router act as an individual broadcast domain. This often helps a lot to manage the networks as it reduces the number of broadcast messages that circulate in a network. However it’s not an ultimate solution, let’s say the no. of devices exceed above 100 or 1000, which demand as many broadcast domains to optimize
